I love this router and it has improved transmission throughout the house by orders of magnitude over the unit it replaced.  However, I have two rooms I would still like to boost a bit more, one bedroom on the 2nd floor and the attached garage directly below. The bedroom usage is straightforward browsing and streaming, the garage usage is eSports gaming (Zwift) for indoor training. I would like to know if a range extender would work, if so, which model(s).  If it is not recommended, what solution would be?

I am not a network engineer, so be gentle.  Thanks!